Gas-analyzing apparatus.



G. A. BURRELL GAS ANALYZING APPARATUS.

APPLICATION FILED FEB. I1, 1916.

vPatented Mar. 21, 1916.

2 SHEETS-SHEET l.

S 0G l G. A. BURRELL.

GAS ANALYZ ING APPARATUS.

APPLICATION FILED FEB. II, 191e.

Patented Mar. 21, 1916.

2 sIIETsfsIIEET 2.

I S 0 C www I r GEORGE A. BUERELL, or PITTSBURGH, PENNSYLVANIA.

` GAS-ANALYZING- APPARATUS.

Specification of Letters Patent.

Patented Mar. 21,1916.

Application iled February 11, 1916. Serial No. 77,785.

(DEDICATED T0 THE PUBLIC.)

To all whom it ma'jz/ concern Be it known that I, GEORGE A. BURRELL a citizen of the United States, and a resident of the city of Pittsburgh, county of Allegheny, State of Pennsylvania, and an employee of the United States Bureau of Mines at Pittsburgh, Pennsylvania, have invented certain `new and useful Improvements in Gas-Analyzing Apparatus, of which the following is a specification.

This application is made under the act of March 3, 1883, chapter 143 (22y Stat., 625) and ,the invention hereinl described and claimed lmay be used by the Government of the United States or any v'of its oiiicers or employees in the prosecution of work for the United States, or by any other person in the United States, without the payment of any royalty thereon.

lVl'y` invention relates'to means for detecting the presence and quantitatively determining the proportion of inflammable gas in mixtures comprising such gas, and bey longs to that class of apparatus in which the inflammable gas ifpresent is burned by the oxygen in the mixture to form products ofless volume than the original constituents,

.the combustion being initiated by means of a metallic filament which is heated by the passage 'of an electric currenttherethrough. -The object. of my invention is to construct a strong, cheap, and compact apparatus `which can be readily carried about and oper ated without the exercise of special skill,

and used for the detection of methane (fire-4 damp) in mines, hydrogen around storage batteries, `carbon monoxld in fluey gases, or the above named inflammable gases as well as benzol, gasolene vapor, or acetylene wherever they may occur in mixtures containing oxygen, such as mixtures. with air.v This object is attained. by the' apparatus illustrated in the accompanying drawings, in which- 4 Figure 1 is a side elevation, partly in section, of my apparatus, Fig. 2 is a similar view of a modification of the ap aratus designed to promote the more rapi cooling of the gases after the combustion as will'be more'fully described,N and Fig. 3 is another p modication in which the battery used to produce the electric current necessary to operate the instrument is contained within the same.

Referring particularly to Fig. 1',the.ap

paratus comprises primarily a modified U-tube consisting of the stout gage glass C and-the metallic tube A joined at their bottoms by the chamber B formed in the lower casing X, and -supported at their tops by the upper casing Y. The limb C terminates in a small chamber H in the upper portion of whlch 1s the nipple R, adapted to receive a vsoft rubber tube (not shown) for convenience in applying a1r pressu-re by the mouth or otherwise. Parallel and close to the gage glass C is a scale-bearing member'O, graduated in a plurality of scales and so arranged that the scale desired 'can be placed next to the gage glass C. The limb A of the U-tube terminates in the combustion chamber D which is provided with a plug P containing an aperture closed by the valve Vhaving the cup K, the construction of which v alve and cup is clearly shown on the drawings. Mounted within the combustion chamber D is a filament F, which I prefer to construct .of platinum wire although otherl suitable materials will readily suggest themselves. Leadskfrom the end of the lament pass through plugs of insulating material to the cemented s o, asfto be tight. Thewhole ap- A paratus may be conveniently lifted and carried by means of the bail T.

The operation of the apparatus is as follows rTo prepare the apparatus for use, the plug P is removed and water is poured into D until it stands at S and Q, in the tubes -C and A, the point `S coinciding -with the zero points of the scales on the tube O. The plug P is then replaced. When it is desired to test a sample ofair for the presence of iniiammable gas, the instrument is carried to the region Where the suspected air is found, and pressure vis applied at R, for example by blowing int'o R through a rubber tube, until water appears in the cup K. During this operation, the valve V is of course o en. If for any reason the cup K is not visi le to the operator, a slight click of 2 l Lirama4 the valve will notify him that the-.Qter has reached it. Comunication between the nipple R and the exterior of the instrument is then cut off, asby pinching the rubber tube between the fingers, and the valve V is plated at the exact point where the sample is to be taken. Airis then allowed to escape from R until the levels of the water in the two limbs of the U-tube 'are equalized, whereupon the chamber D will become filled with a certain volume of-the gas under examination. The valve V is then closed.

- In order to cause the combustion of the inflammable constituent, the terminals of a battery are connected to the binding posts M N, the battery being of suflicient capacity to heat the filament F l to a bright read heat. By means of the window E, the heat# ing of the filament may be observed, showing that the electrical connections are properly made. The combustion of the sample is complete in two minutes or less. During the combustion, the gas in the chamber D expands owing to its increase in temperabon dioxid and water vapor, while the com-V bustion of hydrogen gives only water vapor. This vapor condenses on the cooling of the gases and does not occupy appreciable space. Only the carbon .dioxid .will be left, and this will always have a volume less than the combined volumes of the infiammable gas and oxvgen from which is. formed. Thus, taking methane as a typical example,j the 'reaction 1s as follows:

v 1 volume-t2 volumes=1 volume It will be seen that three volumes'of gas before combustion produce only one volume after combustion, which will cause the liquid to rise in the limb A of the U-tube and to be correspondingly depressed in the limb B, The magnitude of thel depressionproduced will be a function of the percentage of iniammable gas present.

If it is desired to .absorb the carbon dioxid formed, and thus to render the diminution in volume still greater, I may substitute forthe water in -the instrument a suitable solventffor carbon dioxid, such as a solution f of potassium hydroxid. However, I do not find this. to be necessary to secure accurate e5 results. By the. use of the instrument as In Fig. 3, Il have shown little as 0.1% of inflammable gas may be detected.

After the cooling of the gases is completmich will be indicated by the liquid level in the\gage glass C becoming stationary, the liquiddevel vis read off on the appropriate scale on OQneiscale is provided foreach of the iniiammable gases for the detection of which the instrument is to be used, and the scales are calibrated to read directly in percentages of iniiammable gas by the results obtained on mixtures of known composition determined according to the usual methods. .If desired, the filament F may be sur-` rounded by a small chimney to' promote the.

circulation of the gas mixture when the fdament is heated, thereby somewhat reducing the time requiredfor combustion.

In the modification of the apparatus shown in :F ig. 2, the chamber H is so 'con-- structed -a-S to surround the lcombustion chamber, \whereby thecooling of the gases after a combustion is further hstened. This modification of the apparatus is otherwise similar to that shown in Fig. 1, except that the shape of chamber B is somewhat modified to adapt the apparatus to be conv eniently packed in'a case for transportation.

Either of the above forms of the apparatus is intended to employ current from a battery which is separate from the appa ratusJ-and this battery may be either that of a miners electric cap lamp, or a special,

battery carried in the hand or on the back of the operator.

` In Fig. 3,1' have shown a form of the apparatus in which the battery is contained withln the instrument. The battery is G G which are inserted in the liquid-tight tube Z contained within the tube A, the batteries being accessible by removing the plug N. The cells vof'the battery are held in contact with each other'and with the contactscrew L by means of the coiled spring J. The' circuit is opened or closed through the filament F by means of a suitable switch on the outside of the instrument, which is not shown in the drawings. v a convenient form of readily replaceable ignition Elament, though .it vwill be seen that this arrangement can be as readily adapted to either of the other modilicationsof appa.

ratus shown. 'The filament as shown is mounted on a plug U which screws" into a socket W similar to those used for miniature electric lamps. When one filament is burned out, the plu on which it is'mounted can be removed an another inserted without lossof time. The operation of this form of the instrument is the same as that of the other modifications.

'shown as consisting of twol small dry cells It will be understood that various other modifications of the 'apparatus may be found desirable and I do not wish to be understood as being limited to any of the details specifically described herein.

What I claim as new and desire to secure by Letters Patent is 1. In a gas analyzing apparatus two tubes having a connection between their lower extremities, a liquid seal in said connection, a closure for the upper extremity of oney of said tubes comprising a valve, and an ignition member in said closed tube;

2. In a gas analyzing apparatus two Vertical tubes having a connection between their lower extremities, a liquid seal in said connection, a portion of enlarged crosssection at the upper end of one of said tubes, a closure for said tube, and a filament in said enlarged portion adapted to be heated.

3. In a gas analyzing' apparatus a U-tube having a liquid seal in the lower portion thereof. a Scale arranged parallel to one limb of said Utube, means for closing the upper end of the other limb of said U-tube, comprising a valve, a filament mounted in the closed limb, and a source of electrical energy adapted to be connected with said filament.

4. In a gas analyzing apparatus a modified U-tube, a liquid seal in the lowerkportion thereof, means for closing the upper extremity of one limb of said U-tube to form .a chamber above said liquid seal, a metallic filament Within said chamber and adapted to be heated from outside the chamber, and a graduated scale adjacent the other limb of said U-tube.

5. In a gas analyzing apparatus a vertical transparent tube, a movable member adjacent said transparent tube graduated in a plurality of different scales, a second vertical tube, a connection between said tubes at their lower ends, a liquid seal in the junction of said tubes, a cap closing the upper end of said second tube, and a metallic filament within said cap adapted to be heated by the passage of an electric current therethrough.

6. In a gas analyzing apparatus a U-tube having a liquid seal therein, a graduated scale on which to read the liquid level in one limb of said U-tube, a closure for the second limb of said U-tube, an ignition member within said closed limb and above the normal level of said liquid seal, a tube projecting into said second limb of said U-tube, and a source of electrical energy within said tube and connected to said ignition member.

In testimony whereof I aiix my signature.

GEORGE A. BURRELL. 

